On Aug. 20, 2001, Saleh Ibn Abdul Rahman Hussayen, a man who would soon be named a minister of the Saudi government and put in charge of its two holy mosques, arrived in the United States to meet with some of this country's most influential fundamentalist Sunni Muslim leaders.

His journey here was to include meetings and contacts with officials of several Saudi-sponsored charities that have since been accused of links to terrorist groups, including the Illinois-based Global Relief Foundation, which was shut down by U.S. authorities last year.

He met with the creators of Islamic Web sites that U.S. authorities contend promote the views of radical Saudi clerics tied to Osama bin Laden. And among the imams on his travel schedule was a leader of a small religious center tucked into a nondescript office building in Falls Church, the same site used for a time by the spiritual leader of a group of area men indicted in June as suspected jihadists.

On the night of Sept. 10, 2001, Hussayen stayed at a Herndon hotel that also housed three of the Saudi hijackers who would slam an aircraft into the Pentagon the next day, though there is no evidence that he had contact with them.

Hussayen, who was unavailable for comment, is accused of no wrongdoing. The purpose of his meetings remains, in fact, a mystery.

But his travels form a road map to some of the religious and charitable groups in America dedicated to the spread of Wahhabism, the rigid and puritanical strain of Islam dominant in Saudi Arabia. In recent months, authorities have begun to focus on the role of radical Wahhabi clerics and organizations, including some that Hussayen came to see here, in exhorting followers to violence.

Backed by money from Saudi Arabia, Wahhabis have built or taken over hundreds of mosques in North America and opened branches of Saudi universities here for the training of imams as part of the effort to spread their beliefs, which are intolerant of Christianity, Judaism and even other strains of Islam.

"A growing body of accepted evidence and expert research demonstrates that the Wahhabi ideology that dominates, finances and animates many groups here in the United States, indeed is antithetical to the values of tolerance, individualism and freedom as we conceive these things," said Sen. Jon Kyl (R-Ariz.), who has been holding hearings on Wahhabism.

What began as discrete investigations in Idaho, Michigan, New York and Northern Virginia has coalesced in recent months into a cluster of interrelated probes. Prosecutors and FBI agents are trying to determine whether links among the groups suggest a network whose purpose is to incite violent jihad, or holy war, and recruit people to fight it, according to sources familiar with aspects of the investigation.

To date, a variety of charges have been brought against 19 people associated with the groups, and seven have pleaded guilty.

Authorities also are investigating the use of Internet sites, mosques, charities and Islamic conferences as possible venues for recruitment, the sources said. U.S. prisons, where several of the groups have mounted efforts to spread their brand of Islam with outreach programs that include distribution of Korans and other literature, have also come under scrutiny.

The FBI opened a major case file on the suspected network last year, law enforcement sources said, though progress investigating it was initially slow. "The feeling was, 'we see the network, we know it's there, but it's out of our reach. It's so monumental nobody knew how to take it on," one law enforcement official said.

The probe has mushroomed, with agents and prosecutors aided by new access to previously off-limits information gathered over years of noncriminal intelligence investigations, the result of powers gained in part through the USA Patriot Act, the anti-terrorism law approved after the Sept. 11, 2001, attacks.

The investigation is heating up at a time when Washington's relations with Riyadh have been strained by allegations that the Saudi government has done little to rein in huge charities there that have been accused of funding terrorism. The Saudis strenuously deny funding terrorists and say they are cracking down on organizations accused of doing so.

The Saudi government, through its embassy here, declined to discuss any aspect of the probe. Embassy officials agreed in August to forward a request for an interview to Hussayen, but provided no response.

Salem Marayati, executive director of the Muslim Public Affairs Council, an advocacy group, said in an interview that "if a person has recruited people to go commit violence against people abroad, he should be prosecuted." But he said law enforcement authorities cannot trample on constitutionally protected religious freedoms. "Groups should not be targeted for their beliefs, only for their activities if they are criminal," Marayati said.

Wahhabism and Terrorists

Wahhabism took root in the Arabian desert in the 1740s, promulgated by Mohammed ibn Abd Wahhab, who sought to purge what he saw as corrupting influences in Islam and return it to original orthodoxy. Under those principles, non-Wahhabis are considered infidels, and failure to adhere to the faith's tenets draws severe punishment; church and state are one.

Wahhabism found a powerful ally in Mohammed ibn Saud, a Bedouin chief whose conquests spread Wahhabism throughout the Arabian Peninsula, the foundation for centuries of rule by the House of Saud. But when oil wealth opened Saudi Arabia to the West in the 20th century, some Wahhabi clerics became radical opponents of a royal family they no longer saw as keepers of the faith but as decadent apostates.

Some U.S. officials describe Saudi-backed Wahhabism as a philosophical "platform" that terrorists have used to justify holy war. "Al Qaeda has taken advantage of state-supported proselytizing around the world," said senior Treasury Department official Juan Zarate, whose office has taken a leading role in designating terrorist financiers and is pressing the Saudi government to crack down on them, as well.

One of the principal organizations under investigation in the United States is a group the Saudi Embassy has branded as Muslim extremists. It is the Michigan-based Islamic Assembly of North America (IANA), whose webmaster is Saleh Hussayen's nephew: Sami Omar Hussayen, a computer scientist jailed in Idaho on charges he failed to disclose his work for IANA on immigration forms.

IANA, U.S. authorities have contended in Idaho court proceedings, is a powerful engine for groups that promote teachings and religious fatwas -- orders that advocate violence against the United States -- issued by two radical Saudi clerics.

The clerics, Safar Hawali and Salman Ouda, were identified in the first World Trade Center bombing trial as spiritual advisers to bin Laden. Both were jailed for radicalism during the 1990s in Saudi Arabia.

U.S. investigators are focusing on interlocking affiliations among organizations and individuals that have ties to IANA, which has created a dozen or more Web sites whose objective, prosecutors have stated in court papers in Idaho, was the "dissemination of radical Islamic ideology, the purpose of which was indoctrination, recruitment of members and the instigation of acts of violence and terrorism."

According to FBI testimony in those proceedings, Hussayen visited Wahhabis and Salafis -- as non-Saudi adherents are known -- in New York, Michigan, Chicago, Canada and, most significantly, Northern Virginia, a hub for Saudi-backed religious organizations that have wide influence in promoting Salafi doctrine in mosques, at conferences and around the globe on the Internet.

Hussayen met with IANA representatives in Ann Arbor, Mich., according to the court testimony of Idaho FBI agent Michael Gneckow. In court papers, the FBI has described Saleh Hussayen as a financial backer of IANA, an assertion confirmed by his nephew's lawyer in Idaho.

In recent months, 19 individuals who have come under investigation as part of the probe have been arrested or indicted. They include Bassem K. Khafagi, a former IANA president, who pleaded guilty two weeks ago to bank fraud in federal court in Detroit. In Syracuse, five men tied to an IANA affiliate called Help the Needy are charged by federal authorities with sending money to Iraq in violation of U.S. economic sanctions.

In Northern Virginia, 11 men were indicted in June, accused of training to wage jihad with a Pakistani terrorist group. Charges against seven of the men were upgraded last week to conspiring to support terrorist organizations, including al Qaeda. Four others have already pleaded guilty to lesser gun and conspiracy charges.

The indictment also alleged that the men's spiritual leader, Ali Timimi, who has long been associated with IANA, told group members in September 2001 that the time had come for them "to . . . join the mujaheddin engaged in violent jihad in Kashmir, Chechnya, Afghanistan or Indonesia" and that "American troops were legitimate targets of the jihad."

Defense lawyers in the case have argued that the men are being unfairly targeted because they are Muslims.

Timimi has denied that he condoned killing Americans. He has not been indicted, though his attorney has said that he expects Timimi to be charged.

When Timimi's Fairfax house was searched by the FBI this spring, items seized included Khafagi's personal papers, which Timimi was holding for safekeeping. The two had been IANA's representatives to the 1995 international women's conference in Beijing, where IANA argued against Western feminism and defended female circumcision, which is practiced in some Islamic societies.

Investigators at multiple federal agencies are trying to sort out the network's seemingly innumerable links, some of which lead back to the same nondescript office building at 360 S. Washington St. in Falls Church. It is there that Timimi used to lecture at Dar al Arqam, the same religious center frequented by another internationally known Salafi imam, Jaafar Idris. His lectures, like Timimi's, are posted on extremist Web sites around the world, including IANA's.

Idris is president of the American Open University in Fairfax, a "distance learning" center that uses the Web to promote Salafi teaching. The university has received funding from IANA, according to tax records.

Neither Idris nor others at the university responded to requests for interviews, but they were among those in the United States whom Hussayen was scheduled to see, according to sources with knowledge of his trip.

Those sources said Hussayen was also scheduled to visit officials at the Muslim World League, a multibillion-dollar, Saudi-based umbrella charity organization whose U.S. offices are at 360 S. Washington St. Muslim World League officials declined to be interviewed.

The Muslim World League office was raided in March 2002 by Treasury Department agents as part of an investigation into a Herndon-based network of Saudi-financed charities and companies suspected of ties to al Qaeda, the Islamic Resistance Movement (Hamas) and the Palestinian Islamic Jihad. The Muslim World League and its offshoot, the International Islamic Relief Organization, have been the subjects of terrorism financing inquiries in the United States and several other countries.

Hussayen also was scheduled to meet with officials of the World Assembly of Muslim Youth (WAMY), another huge Saudi-based charity headed by the Saudi government's minister of Islamic affairs, according to sources knowledgeable about the investigation. WAMY's U.S. office on Leesburg Pike in Falls Church was incorporated by bin Laden's nephew, Abdullah bin Laden, and operated by him until the Sept. 11, 2001, attacks.

Bush administration officials have pressed the Saudi government to clamp down on the Muslim World League and WAMY, according to federal law enforcement sources, and both are defendants in civil lawsuits filed by families of the victims of the attacks.

Maher Hanania, attorney for WAMY in the United States, denied that WAMY has ties to IANA and said that Hussayen did not meet with WAMY officials while he was in the United States. WAMY has not been criminally charged in any country with supporting terrorism, he said. He acknowledged that WAMY's office here has been under FBI investigation, but said that thus far "the FBI has found no wrongdoing. . . . As to our understanding, the FBI has closed its file on WAMY." The FBI would not comment.

Recent Senate testimony about Khalid Mishal, a Hamas leader who has praised suicide bombers, speaking at an October 2002 WAMY conference in Riyadh, has prompted demands on Capitol Hill that the Bush administration freeze the organization's assets. Hanania said that while Mishal spoke at the conference, that is evidence only that WAMY promotes free expression. WAMY, he said, does not "condone his thinking or policies."

Other featured speakers at that conference included Ouda, Idris and Saleh Hussayen.

IANA conferences in the United States began drawing the scrutiny of terrorism researchers a decade ago because of their heavy Wahhabi and Salafi bent. According to the Investigative Project, a terrorism research group that has monitored Islamic extremists, a senior al Qaeda recruiter, Abdelrahman Dosari, spoke at three IANA conferences in the early 1990s.

FBI and Treasury officials said they believe some Islamic conferences, as well as Web sites that extol radical Islam, are vehicles in the United States for recruitment and fundraising by terrorist groups.

Until it was modified this year, for example, IANA's Islamway.com Web site offered Arabic-language videos with graphic scenes of jihadist combat. "Martyrs of Bosnia" contains footage of al Qaeda members, and suspected al Qaeda members are featured in a second such film called "Operation Badr."

The U.S. government has shut down numerous Web sites that promote terrorism, but new ones pop up quickly.

IANA has received $3 million since 1995, according to FBI court filings, much of it from abroad, including $100,000 from Saleh Hussayen. Government officials are tracing the finances of IANA and related groups.

"It's much more than about the money they raise. It's proselytizing, recruiting and radicalizing people in this country and other places across the globe," said Matthew Levitt, a former FBI counterterrorism official now with the Washington Institute for Near East Policy.

The Idaho visa fraud indictment against Sami Hussayen contends that he administered a Web site associated with IANA that expressly advocated suicide attacks and using airliners as weapons. Court papers filed by the government assert that an IANA Web site published a fatwa issued by Ouda on June 19, 2001, that "justified and advocated suicide bombings," and that two months later, on Aug. 16, an IANA Web site in Canada published an "invitation to jihad."

"If Sheikh Ouda holds up a banner saying, 'Go Kill the Military,' a true believer takes that as an order to take action," one official involved in the investigation said.

David Nevin, attorney for Sami Hussayen, said Ouda and Hawali are "observed figures" in Saudi Arabia, not proponents of violence. Nevin said Saleh Hussayen was a backer of IANA but not a principal in the organization. He declined to discuss Hussayen's visit to the United States, other than to say that "it was utterly and completely innocuous and without connection to anything improper."

Within five months of his journey, Hussayen would assume the post of general president of the Grand Mosque and the Prophet's Mosque, a position that involves him in the administrative affairs of the kingdom's charities.

Hussayen has a background in Saudi-backed charities. Virginia incorporation records show that during the 1990s, he was a director of the SAAR Foundation, a charitable organization that was at the center of a sprawling conglomerate of Muslim institutes, companies and religious groups that are under federal investigation for alleged ties to terrorist organizations. SAAR's offices in Northern Virginia were raided in 2002, kicking off the government's most wide-ranging probe to date into suspected terrorist financing. This week, Abdurahman Alamoudi, a prominent Muslim activist affiliated with the SAAR network, was charged with illegally doing business with Libya.

Nancy Luque, attorney for two top officials of the defunct SAAR network, confirmed that a Saleh Hussayen had served as a SAAR director, but suggested that her clients did not know of his importance in Saudi Arabia.

Saudi Embassy Donates Korans

In his travels in Northern Virginia, Hussayen also scheduled a meeting with the leader of the Islamic Foundation of America (IFA), a Springfield organization that operates a school, a mosque and an active prison outreach program, at one time sending out about 40 Korans a day provided by the Saudi Embassy, according to spokeswoman Narmeen Slim.

The group's founders include Idris and an austere and enigmatic Saudi cleric, Ibrahim Ibn Kulaib. The foundation has chosen a run-down warehouse just yards from the Interstate 395 Mixing Bowl from which to mount its stated mission of "spreading the message of Islam throughout the U.S. and all over the world."

IFA's headquarters have been visited by well-known Wahhabi and Salafi leaders. Among those who have spoken there are Timimi and Sirhaj Wirhaj, a New York imam who was an unindicted co-conspirator in the 1993 World Trade Center bombing.

The most intriguing aspect of Hussayen's journey may be entirely coincidental: his brief proximity in a hotel near Dulles International Airport to three of the Sept. 11, 2001, hijackers the night before they crashed Flight 77 into the Pentagon. On the night of Sept. 10, Hani Hanjour, Khalid Almihdhar and Nawaf Alhazmi checked into the same hotel, a Marriott Residence Inn.

The FBI has examined hotel videotapes and interviewed employees, but has found no indication that Hussayen and the hijackers interacted, law enforcement sources said. After the attack, an FBI agent interviewed hotel guests, including Hussayen and his wife, but did not get very far.

According to court testimony from FBI agent Gneckow earlier this year, the interview was cut short when Hussayen "feigned a seizure, prompting the agents to take him to a hospital, where the attending physicians found nothing wrong with him."

The agent recommended that Hussayen "should not be allowed to leave until a follow-up interview could occur," Gneckow told the court. But "her recommendation, for whatever reason, was not complied with," he said.

On Sept. 19, the day air travel resumed, Hussayen and his wife took off for Saudi Arabia.

Research editor Margot Williams contributed

to this report.

In Idaho, federal agents remove evidence from the home of Sami Omar Hussayen, webmaster for an Islamic group.Two summers ago and a month before the Sept. 11, 2001, terrorist attacks, Saleh Ibn Abdul Rahman Hussayen, left, toured the United States, with meetings and contacts with several Saudi-sponsored charities that have since been accused of links to terrorist groups.Sami Omar Hussayen, right, is jailed in Idaho on charges that he failed to disclose his work for the Islamic Assembly of North America (IANA) on immigration forms. Sami is the nephew of Saleh Hussayen, now a minister of the Saudi government.The Muslim World League, a multibillion-dollar, Saudi-based umbrella charity organization, has U.S. offices at 360 S. Washington St., Falls Church. The Dar al Arqam religious center is also located at this address.